SS_cache missing

I had a strange problem, with a file suddenly disappearing. The file is /sapphire/cache/Cache.php. It happened on multiple websites, so I thought it was my webhost but I googled "fatal error ss_cache" and found another website http://www.seahillpress.org/ with the same problem.

@rokryan: well I don't know about seahillpress.org but I know that my websites are hosted on dreamhost and it seemed there was some problems when transferring my sites over a new server or something like that. Basically, just upload the file again with the SS_Cache class and you are good to go. It's quite a strange issue anyway, but it's not a hacking issue or anything similar.